Not Applicable.
Not Applicable.
This invention relates generally to holders for soapstone markers, and, in particular, to a soapstone holder which allows for easy advancement a stick of soapstone as the soapstone stick wears down.
Soapstone is often used as a marker to mark various materials. Soapstone marking sticks are commonly provided in lengths of about 5xe2x80x3 and have cross-sectional dimensions of about 0.2xe2x80x3xc3x970.5xe2x80x3. Soapstone sticks are fragile or brittle, and, are easily broken during use if not held in a protective holder. Such broken sticks are often too small for further use, and hence are discarded. Various holders have been designed to protect soapstone sticks to prevent breakage of the sticks during use. However, such prior holders have drawbacksxe2x80x94they are expensive to produce, difficult to use, and do not allow for easy advancement of the soapstone stick as it wears down.
Briefly stated, a holder for marking material is provided which is simple to assemble and operate, and which allows for the gravity feed of the marking material to advance the marking material in the holder. The holder is a two piece assembly which includes a housing and a collet which moves axially in the housing. The housing is hollow and open at its opposite ends. It has a first side wall and a second side wall opposite the first side wall. At least one, and preferably two or more cavities are formed in the housing first side. The cavities each have a sloped outer surface, and at least one of the cavities includes a shoulder which extends from the cavity sloped surface to the inner surface of the first wall. The second side wall has an inner surface shaped to correspond generally to the shape of the marking material.
The collet includes a body and an arm extending from the body. The collet is sized such that the at least a portion of the collet body extends from the top of the housing, and the collet arm extends from the base of the collet body substantially to the opposite end of the housing. The collet arm has an inner surface and an outer surface. The arm inner surface is shaped to correspond generally to the shape of the marking material. The arm has at least one wedge, and preferably two or more wedges, formed on its outer surface and positioned to be received in said housing cavities. The collet is movable between an extended position in which the sloped surface of said housing cavity engages the collet arm wedge to urge the collet arm transversely towards the housing second wall to frictionally grip the marking material in the holder and a second position in which the wedge is received in the housing cavity such that no transverse force is applied to the collet arm, and the marking material can move freely relative to the holder.
The holder also includes a biasing element to bias the collet to the extended position. The biasing element is preferably a spring which has a generally S-shape. The spring has a first end in contact with a base of the collet body and a second end which engages the housing. The housing includes an opening, and, the spring includes a finger at its second end. The spring finger is received in the housing opening. Preferably, the spring is integrally formed with the collet.